1. Field of the Invention
The invention relates generally to product forming devices and particularly to rotary forming devices and methods of using the rotary forming devices to produce products such as filled and unfilled “pillow” shaped products.
2. Description of Related Art
Products such as kibbles or biscuits that are “pillow” shaped are currently made via a stand alone crimping device that is typically situated two to three meters away from an extruder exit. Ropes of extrudate are then conveyed to this crimping device and pillows are formed and sealed through the use of a “sprocket” crimping device. This type of crimping device is prone to fouling, is limited in throughput, and is expensive, e.g., requires a large capital investment. Extruder throughput rates are also limited by other traditional crimping equipment.
Dual multi-textured food products can also be made using conventional crimping equipment. The dual multi-textured food products can be made by co-extruding a cylindrical outer shell of one material and inner filling or core of a different material. If the viscosities of the shell and core material are high enough, the extruded ropes can be cut by rotating cutting blades into smaller pieces or kibbles. Conversely, if the core material is of a lower viscosity, it may flow away from the shell after it is cut. Therefore, instead of only cutting the ropes into smaller pieces, the shell has to be crimped at the ends to enclose and retain the flowable core. Production of crimped kibbles such as powder filled or granular filled kibbles is also a method of protecting sensitive ingredients in the core or of occluding objectionable aromas.
The current technology for producing center-filled kibbles where the core layer is completely enclosed requires a separate piece of crimping equipment after extrusion and an extension of the production line. Further, the method of pulling and crimping the co-extruded ropes are fraught with problems such as maintaining a continuous rope feeding into the crimper and avoiding entanglements. Consequently, these problems reduce production output of the sealed or crimped center-filled kibbles. There is, therefore, a need for new devices and methods for forming “pillow” shaped products, whether filled or unfilled.